Moshkatiuk A. Research of heat exchangers of small energy conversion systems under operating conditions

Dissertation is devoted to theoretical and experimental research, which is aimed at increasing the efficiency of commercial refrigeration systems of various structures, taking into account external negative effects on heat transfer and aerodynamics of devices. Refrigeration machines and heat pumps of low and medium capacity are classified as energy conversion systems for commercial purposes, therefore, energy costs for the consumer of these machines are the main concern and must correspond to those planned during design. The analysis of processes occurring in elements of a refrigeration machine or a heat pump in the design process should be based on a clear understanding of the criteria by which the construction of an economic model and an assessment of work in real conditions will be carried out. Air condensers are widely used in commercial systems and in regions with limited water resources. They are the only option among heat removal systems. The efficient operation of the air condenser is impeded by external conditions associated with air pollution by gases, dust, soot, fluff etc. The result is the growth on external surfaces of various solid fouling which leads to increased noise in the machine, deterioration of heat transfer, increased energy consumption and disruption of the entire system’s stable operation. Existing scientific and practical recommendations aimed at solving problems of fouling formation taking into account operating conditions’ peculiarities of commercial equipment are clearly not enough, as they do not contain universal engineering calculation methods making it possible to predict real operating conditions at the design stage. Research aimed at improving the efficiency of commercial refrigeration systems requires a comprehensive approach to making rational engineering decisions. Therefore, further theoretical and experimental studies of air condenser contamination processes are relevant. Their results will complement the global experimental database of solid fouling analysis, methods of control and solid fouling elimination.